Semi-submerged cargo transport system

ABSTRACT

There is provided a semi-submerged cargo system for the transport of cargo under ice. The system comprises a submerged vessel having navigational and cargo sections and a propulsion section; connected to a surfaced bridge, housing the crew and controls, by an ice-cutting mast. The propulsion section drives the vessel under the surface of the ice. Although the propulsion section is preferably an integral part of the vessel, it may exist as a separate tug which tows or pushes the vessel.

O United States Patent 1 91 [111 3,868,920 Schirtzinger 1 -Mar. 4, 1975[54] SEMl-SUBMERGED CARGO TRANSPORT 3,494,607 2/1970 Rusch 114/219SYSTEM 3,517,633 6 1970 Wanzer 114/151 3,521,592 7/1970 Rosner et a1114/42 [75] Inventor: Joseph F.Sch|rtz|nger, Pasadena, 537 4 1 970Calif. 3,554,527 1/1971 [73] Assignee: Air Logistics Qorporation,Pasadena, Cahf. 3 4 35 3/1972 3,669,052 6/1972 [22] Flled. Nov. 1, 197113188013 5/1960 v FOREIGN PATENTS OR APPLICATIONS Related ApplicationData 402,450 3/1943 ltaly 114/16 R [63] Continuation-impart of Ser. No.74,820, Sept. 23, 1,204,640 9/1970 Great Britain 114/16 R 1970,abandoned.

Primary E.\'aminerTrygve M. Blix U-S- s R, i 1 Assistant E -an inerGa]en Barefoot [5 Int. Cl- Attorney Agent or Finn christie Parker & Hale[58] Field 01' Search 114/16 R, 219, 74 A, 74 T, 114/40,42, 151,235 B,74 R; 241/102, DIG. 30; 293/71 R, 71 P, 1310. 2, D16. 3, 1; 37/43 [57]ABSTRACT There 15 provlded a seml-submerged cargo system for 5References Cited the transport of cargo under ice. The system com-UNITED STATES PATENTS prises a submerged vessel having navigational and3 43 cargo sections and a propulsion section; connected to 33 5 222 2 Ra surfaced bridge, housing the crew and controls, by 5 2 H1962 Denips etg 14/735 B an ice-cutting mast. The propulsion section drives the310331151 5/1962 Sheehanm. 114/219 Vessel under the Surface of theAlthough the 3,067,712 12 1962 Doerpinghaus 1 114/74T P Section isPreferably an integral P the 3,085,533 4/1963 Goryl et a1. 114/16 R e itay e ist as a separate tug which tows or 3,179,397 4/1965 Cleevemane181. 114/219 pushes the vessel. 3,225,731 12/1965 McCulley 1. 114/2193,468,277 9/1969 Rosner et a1 114/42 46 Clam, 11 Drawmg Flgures PATENTED41975 SHEET 1 BF 5 PATENTED 75 sum 2 0f 5 PMENTED 4W5 3.868.920

SHEET 3 [IF 5 1 SEMI-SUBMERGED CARGO TRANSPORT SYSTEM BACKGROUND OF THEINVENTION This is a continuation in part of my application, Ser. No.74,820 filed Sept. 23, 1970 now abandoned.

The Arctic shores of Alaska and the outlying islands have been shown tobe capable of producing large quantities of minerals and petroleum.However, as yet, no satisfactory year-round means of transportingextracted values to market has been made available.

Normally, pipe lines would have been one of the indicated means fortransporting fluids or fluidizable materials. The conditions of theArctic, however, make their construction and operation difficult,uneconomical and potentially destructive to the environment.

The north slope of Alaska in which most of the petroleum wells arelocated consists of a layer of slow growing vegetation, muskeg ortundra, on the surface of partially frozen soil or permafrost formed byconsolidations of gravel and ice.

Any disturbance of the layer of protective vegetation exposes thepermafrost to thawing during the summer. This creates deep erosiongullies that continue to increase in depth during each successive summerseason. No satisfactory method has yet been presented to permit theinstallation of insulated or bare pipe lines in this frozen and unstablesoil to carry oil at temperatures high enough to permit it to flowfreely.

The use of heavily reinforced ice-breaking tankers has also been triedon an experimental basis using a water ballast. If during the trial, thetankers hull plates were destroyed by ice a disaster would have occurredhad the tanker been carrying crude oil instead of water. In addition,there is no indication that a tanker would provide satisfactoryyeanround means of transportation.

Thus, no truly practical means has yet been presented which would serveto transport petroleum and other mineral values from Arctic shores toconsuming areas of the United States and other parts of the world.

SUMMARY OF THE INVENTION According to the present invention, there isprovided a semi-submerged transport system for the safe, economical andyearround transportation of cargo under The semi-submerged transportsystem comprises a submerged vessel having a navigational section and acargo section and a means to propel the vessel under the surface of theice, this means comprising a submerged propulsion section, a surfacedbridge and an interconnecting ice-cutting mast.

The navigational section which is generally located in the bow of thevessel contains means to adjust the depth of travel and means to monitorthe under-ice travel ofthe vessel. The cargo section provides aplurality of cargo compartments and contains means to adjust ballast sothat the vessel may always be operated at a slight positive buoyancy.

The submerged propulsion section contains means for propelling thevessel, fuel and preferably at least a portion of the prime source ofpower and is preferably an integral part of the vessel.

The surface bridge contains means to monitor and control the operationof the system and quarters for the operating crew.

The interconnecting ice-cutting mast contains means for cutting narrowpaths through the ice'and provides conduits between the surfaced bridgeand the propulsion section.

In a preferred construction, the navigational and cargo sections areprovided with resilient cushioned runners along the top surface of thevessel to permit the vessel to glide along the undersurface of the ice,and at least longitudinal upper flotation-cargo tubes and longitudinallower cargo-ballast tubes for adjusting buoyancy to and in maintainingthe vessel at a slight positive buoyancy. The cargo compartments may belongitudinal tubes and are preferably divided by flexible diaphragmswhich permit imcompatible cargos and ballast to be carried in the singlecompartment.

In addition, the vessel is provided with horizontal and vertical thrustports in the navigational section to facilitate raising and lowering thevessel and in docking operations.

In the preferred mast construction, ice-cutting means are driven fromthe propulsion section and consist of a pair of adjacent shafts. On eachthere is mounted a plurality of parallel ice-chipping discs containingicecutting teeth which preferably intersect, in parallel relation, thevertical bisecting plane of the mast. The shafts rotate in an opposeddirection, the forward peripheries of each disc rotating in outboarddirection. This functions to cause the chipped ice to be forced up andaft in a direction opposed to the direction of movement of the vessel.Preferably the mast in the zone associated with the ice chipping discsare protected by a resilient or reflective covering to deflect chips ofice thrown against the mast. In addition the angle of the mast orice-chippers relative to the vertical is from about 10 to about 45 toprevent a pitch which would tend to raise or lower force on the vesselas it advances through the ice.

In the preferred bridge construction a platform is provided to receivehelicopters which attend the operating crew.

An alternate embodiment, a means for propulsion which amounts to thepropulsion section, the surface bridge and interconnecting ice-cuttingmast may be operated as separate attending tug, which either tows orpushes the vessel. In these embodiments, the attending tug is providedwith its own navigational aids to monitor the passage of the system orthe position of the vessel under the surface of the ice.

THE DRAWINGS FIG. 1 is an illustration of relative size and opera-.tional position of the semi-submerged cargo transport system of thisinvention.

FIG. 2 is a more detailed representation of a semisubmerged transportsystem of this invention illustrating the preferred angle a of thecutting blades to the vehi cle.

FIG. 3 is a detailed illustration of the thrust port system used inaltering the position of the vessel.

FIG. 4 is a detailed representation of the surfaced bridge andice-cutting mast showing the protective resilient covering for the mast.

FIG. 5 is a more detailed representation of the inclined ice-cuttingmast illustrating in part its several functional operations includingthe detail of a reflective protective covering for the mast.

FIG. 7 is a full operational representation of the semisubmerged cargotransport system.

FIG. 8 is a representation of a towed submerged vessel and attendingsemi-submerged tug.

FIG. 9 is a representation of the submerged vessel and attendingsemi-submerged tug in pushing operation.

FIG. I is an illustration of an ice-bound service port for thesemi-submerged transport system.

FIG. 11 is an illustration of the preferred runners employed to protectthe vessel shown with reference to the cargo section.

DESCRIPTION According to the present invention there is provided asemi-submerged system for the safe, economical and year-round transportof cargo from ice-bound areas such as the Arctic.

This transport system comprises, generally, a fully submergible vesselhaving navigational and cargo sections and means to propel the vesselunder the surface of the ice comprising a propulsion section connectedto a surfaced bridge by a semi-submerged ice-cutting mast. While thepropulsion section is preferably an integral part of the vessel, it mayin the alternative, be operated as a separate attending tug which pushesor tows the vessel.

The semi-submerged transport system is adapted to be operated at theslight positive buoyancy. In this system, the navigational sectionlocated ahead of the cargo section contains means to alter the relativedepth of travel of the vessel and normally contains means to monitor thepath of travel under the ice.

The cargo section contains a plurality of compartments preferablycontaining flexible diaphragms which allow incompatible cargos orballast to be carried in the same compartment. It is also preferablyprovided with a plurality of flotation-cargo tubes and cargo-ballasttubes which are used to adjust the vessel buoyancy.

At least the vessel is also provided with cushioned runners along itsupper surface which permits it to meet obstructions without damage andglide along the undersurface of the ice and the mast provided with aresilient coating or reflective covering to protect the mast against icedamage.

The propulsion section contains the fuel and means of propulsion. Theprime source of power generation, preferably gas turbines, are locatedin the propulsion section and/or the surfaced bridge.

The surfaced bridge contains means to monitor and control the operationof the transport system and provides quarters for the operating crew.

The ice-cutting mast which connects the bridge to the propulsion sectionalso provides conduits for the transport of fuel and power between thebridge and the propulsion section and air where the prime means of powergeneration is in the propulsion section.

With reference now to FIG. 1, the semi-submerged cargo transport systemof this invention comprises a navigational section 12, a cargo section14 and an integral or separate propulsion section 16 which issemisubmerged and comprises a submerged propulsion section 15, asemi-submerged ice-cutting mast l8 and a surface bridge 20 above thesurface of ice 22, mast 18 being provided with ice-cutting means to cuta path through the layer of ice.

. 4 With reference now to FIGS. 1, 2 and 3, the cargo section 14 of thesemi-submerged transport system I0.

is elongated and has a streamlined bow 24. impactresilient runners 26,which permit the vessel to glide, when necessary, along the undersurfaceof the ice. The runners, preferably have foam-filled layers for shockabsorption and for deflecting the bow down and out of the path of anydownwardly projecting ice.

With reference to FIG. 11, in the preferred construction of the vesselthe runners 26 are constructed of open celled foamed layers 27 whichdecrease in density in the vertical direction. The foam is covered witha porous nylon skin 29 and coated on the top with an abrasive resistantcoating 31 such as a-urethane or an epoxy. The porous nylon skin permitswater to enter foam cells. When the runner strikes an obstruction thecontained water is released thereby absorbing the force. The abrasionresistant top coating, in turn, protects the foam and nylon skin fromabrasive forces. As the foam has a density gradient resistance tocompressive force will increase with compression and as energy isabsorbed.

It is also provided with diving vanes 28 used to control the depth oftravel in water to compensate for the variations in ice thickness. Thesystem is also preferably provided with rear diving vanes 30 in orderthat a change of depth during travel may be realized without a materialchange in attitude.

With particular reference to FIG. 2, which reference is equallyapplicable to FIGS. 1, 4, 8 and 9, at least the ice chipper or cuttersare preferably positioned at some angle a to the vertical and preferablyfrom about l0 to about 45 to the vertical. Within those ranges, pitchforces induced during the cutting action of ice chippers are minimizedto minimize or eliminate any tendency for the vessel to rise or lowerdue to cutting action.

With particular additional reference to FIG. 3, the navigational sectionI2 is also provided with a thrust system 32 comprisingintercommunicating thrust ports 34, 36 and 38. At least thrust ports 34and 36 contain shaft or electric driven props 40 or water turbines.Thrust ports 34 are used in raising or lowering the vessel, particularlyat low speeds. Thrust ports 36 which are horizontally oriented are usedto alter the sideward motion of the vessel and are particularly usefulin docking operations. Port 38 is used as a reverse thrust port to alterthe forward movement of the vessel and acts as a brake. It may containits own propeller, but preferably it contains a one-way flap or valve42. When ports 34 and 36 are in operation in a manner which forces watertowards the center of the thrust system, valve 42 opens and provides anet thrust outwardly from port 36 which opposes to the forward motion ofthe transport system.

Vertically oriented thrust ports 34 are most important to the operationof the vessel. As already indicated, the vessel 10 is operated at aslight positive buoyancy in order that it will not be subject tocompressive forces when at rest, due to settling of the vessel. Thetendency of the vessel to rise is overcome at normal operating speeds bya slight downward force vector created by a pitch in diving vanes 28 and30. When speed is reduced, however, the buoyant force may overcome thecounteracting force porvided by the vanes and the vessel may tend torise. This may occur, for instance, when an oppressive mass of ice isencountered which slows the vessel due to the amount of icecutting whichmust be accomplished. Thrust ports 34 are set into operation to providean upward thrust to maintain the vessel at a desired depth.

Thrust ports 34 also play an important part during the launchingoperations. The cargo vessel may, for sundry reasons, come to rest atperiods of time along the undersurface of the ice, either because ofrepairs, servicing of the crew, or merely loading, unloading or transferoperations. The undersurface of the ice will present an obstruction tothe launching of the vessel either because of protrusions which extendinto the water, or mere friction. These thrust ports, therefore, providean instant means to force the vessel downwards when operation is toresume.

Horizontal thrust ports 36 play an important part in maneuvering thevessel during docking operations as they can be effectively used as thetransport system approaches a dock or port to provide a sideward motionin order to properly mate the vessel with portside or dock facilities.

The navigational section may also be provided with elevation and depthsensors, such as sonar devices, (not shown) which automatically, orthrough responsive action by the monitoring crew, adjust the operationof vanes 28 and 30 and, when necessary, thrust ports 34 and 36, toadjust the position of vessel relative to the undersurface of the ice,the floor of the seaway, or a servicing platform, vessel or port.

To monitor the passage of the system under the ice, the navigationalsection is also provided with TV camera 44 and lights 46.

For maximum versatility, the cargo section 14 is preferablymulti-compartmented with each compartment 48 divided by a flexiblediaphragm 50 which may be moved from one side of the compartment to theother by differential pressure when fluids are pumped into thecompartment. This permits, for instance, a clean water ballast to becarried in one side of the diaphragm without contaminating the cargo onthe other side. Ballast water may be discharged at the mooring when thecargo in the other portion of the compartment, such as petroleum, isbeing loaded without attendant pollution of surrounding seawater. Inaddition, flexible diaphragms may be used to keep incompatible liquidsfrom mixing when mixed cargos are carried in the same compartment.

Cargo section 14 is preferably provided with a plurality of longitudinalflotation-cargo tubes 52 and ballastcargo tubes 54. These tubes may beused as containers for cargo and heavy slurry ballast when the maincargo is petroleum or another cargo lighter then seawater, or may beused as air flotation chambers when the cargo is more dense than thesurrounding water.

The buoyancy of the system 10 is normally controlled by a regulatedproportion of air and/or seawater in upper flotation cargo tubes 52 andballast in lower car go-ballast tubes 54, the loading of the tubes andcontainers being such that the system 10 is always maintained at aslight positive buoyancy. This assures that it will come to rest at theundersurface of the ice to avoid hydraulic pressures at increased depthand permit the vessel to run on the water surface when the sea is open.The cargo compartments 48 and tubes 52 and 54 are fed through servicingports 56, located at one or more positions on each side of the hull aswell as in the bow and stern of the cargo section.

While the cargo compartments 48 may be fairly large, they may also belongitudinal tubes illustrated in FIG. 9, similar or identical to tubes52 and 54. Preferably, they and tubes 52 and 54 are also divided byflexible diaphragms which permit incompatible cargoes to be carried inone tube. Each container and/or tube is provided with a suitable ventsystem which permits air and/or water displacement during loading andunloadmg.

The cargo section may carry a wide variety of prod ucts including amongothers, petroleum products, chemicals, gases, fluidizable minerals,slurries such as ground ores, foodstuffs and the like. They may, forinstance, be used to transport raw materials from Arctic areas andreturn needed supplies to such areas.

Cargo section 14 may be of rigid or semi-rigid construction. Rigidconstruction is used for unitized construction and may be achievedthrough the use of steel, aluminum, fiberglass, reinforced resins andthe like. Semi-rigid construction may be used when the cargo is towed.The towed vessel may employ a structure substantially as set forth inU.S. Pat. No. 3,296,994 incorporated by reference, and may, as disclosedtherein, be of expandable construction. This construction isparticularly useful when the cargo compartments are longitudinal tubeswhich can be removed or added to meet fluctuations in cargo supply.

Submerged propulsion section 16 providing propulsion means 15 isattached to ice-cutting mast 18 which is, in turn, connected to asurfaced bridge 20. The submerged portion contains the prime means ofpropulsion, typically twin screw propellers or a water turbine at itsstern, and houses the fuel compartment; where necessary, a ballastcompartment and, where desired, contains the water supply for the crewin bridge 20. The fuel and water compartments preferably are flexiblediaphragms or are of bladder construction which allow the water and fuelto be supplanted by a seawater ballast as they are consumed withoutcontamination. This allows overall buoyancy to remain fairly constantthroughout operation. It is steered by rudder 57 and may havestabilizing fins 59.

The prime source of power may be gas turbines, steam generator, internalcombustion engines, nuclear engines and the like, with gas turbinesbeing preferred for simplicity of operation. Although the prime sourceof power generation may be housed in the submerged propulsion section 16and/or the bridge 20, it is preferably located in the submergedpropulsion section, with the air required for combustion being providedthrough mast 18 which also serves as the exhaust port and will behereinafter explained.

In addition to providing the power for propulsion which is normally inexcess of about 40,000 h.p., the power source also provides power tooperate the icecutters which is generally in the order of 6,000 h.p.,and generates the electricity for operation of the entire transportsystem.

When the prime source power generation is contained in the bridge, poweris transmitted to the propulsion section through shafts in mast l8.Alternately, the power can be converted to electrical energy which istransmitted to motors in the propulsion section.

Surfaced bridge 20 houses crew, the operational sys- [em for monitoringand controlling the cargo systems and normally provides landing platform58 for receiving helicopters and VTOL craft which attend to thetransport system. The lower surface of bridge 20 is serves as a conduitto transport needed supplies from.

the submerged portion to the bridge and, where the prime source of powergeneration is located in the submerged portion of the propulsionsection, air to the prime source of power generation, and a conduit forexhaust.

With reference now to FIGS. 4, and 6, there are shown in greater detail,bridge and the mast 18, which is preferably inclined, of thesemi-submerged cargo system of this invention and illustrates the detailof the operation of an ice-cutting mechanism which may be used.

Bridge 20, as indicated, houses the controls system and the crew. It mayalso, where desired, house all or part of the prime source of energy,but will normally always house an energy source for providing the energyrequirements of bridge 20. This may be a gas turbine located below thebridge and supported by mast 18 or may, where desired, be an electricalmotor driven from prime energy source located in the submerged portionof propulsion section 18, and transmitted to the bridge through conduits62 in mast 18. As indicated, bridge 20 is provided with landing deck 58for receiving helicopters 60 or VTOL craft, which are used to serveneeds of the operating crew.

In addition to a normal observation area 64 the bridge is provided withother navigational aids such as radar 66, antenna 70 and TV receiver 72,lights 74, and other navigational requirements such as fog horns and thelike.

With further reference to FIGS. 4, 5 and 6, the icecutting system 76functions to break and chip the ice in the path of the moving tug andthrow ice chips outward and aft. As the aft component of the cutteraction is in the direction of the propulsion forces, it aids in theforward motion of the tug.

With particular reference to FIG. 5, the mast also provides a pluralityof conduits 62 which provide communication between bridge 20 and thesubmerged propulsion section. Fuel, power, air for combustion andexhaust may be transmitted through them depending on the constructionused and the location of the source of power generation.

One conduit may, for instance, contain a ladder 78 for access to theengine room when it is located in the submerged portion section. Theymay also be provided with a conveyor system and lines to transport waterand supplies to the bridge where the submerged section is employed forstorage of crew needs. When the engines are submerged, air is drawn inan intake 80 in bridge 20 or a comparable one in mast 18. The exhaustmay be ejected to the water but is preferably returned through insulatedconduits to bridge 20 to provide indirect heating for the cabin. Exhaustgas may also be ducted through controllable vents to aid instabilization.

With reference to FIGS. 4, 5 and 6, the preferred icecutting system 76comprises shafts 82 on which there is mounted in parallel relationship,a plurality of discs 84, each disc containing a plurality of chippingteeth 86. The discs are preferably positioned such that the path oftravel of the teeth of eachdisc overlapping the path of travel of theteeth mounted on the discs of the adjacent shaft but in a differentparallel plane. The discs rotate in an opposed direction cutting the icein a manner such that chippedice is thrown out and aft as a path is cutthrough the ice.

At regular intervals along the length of mast 18 are located loadbearing ridges 88 which serve to support the shafts under the cuttingloads it must sustain, and shroud 90 which covers the ice-chippingmechanism when the vessel is operated in open water.

Although the ice-chipping apparatus has been described in terms of usinga cutting system comprising bladed discs whose teeth intersect a commonplane, it will be appreciated that other cutting mechanisms may also beused. There may be employed, for instance, he lical intermeshing cuttingblades which rotate in an opposed direction to achieve the sameice-breaking function. Alternately, there may be employed reciprocatingsaw-like cutters which chip and lift the broken ice away from the pathof travel of the tug.

With reference to FIGS. 4, 5, and 6 whatever ice chipper or cuttingmechanism is employed there exists a problem of damage to mast 18 due tochips of flying ice. To overcome this problem the port and starboardedges of mast 18 should be rounded as shown in FIGS. 4, 5 and 6 andprotected by reflective cover 19 shown in FIG. 5 or coated with anelastomeric material 21 shown in FIGS. 4 and 6 to deflect the projectedchips of ice.

With particular reference to FIG. 5, the reflective coating may be aglass fibre reinforced shield made of a material such as Stratoglaswhich is composed of strands of cross oriented glass fibres bound by aresin such as an epoxy resin, a polyester and the like. When employed asshown in FIG. 5 the sheath of the reflective covering 19 may be hollow,filled with sea water or an inner resilient material such as a foam oran elastomeric material 21. The reflective shield is secured to mast 18only at the ends thereof with any resilient foam or elastomeric material21, if provided, being contained between the reflective shield 19 andmast 18.

In the alternative and with particular reference to FIGS. 4 and 6, theremay be employed conventional coatings of an elastomeric material 21 suchas a butadiene rubber, a foamed polymer such as foamed lower olefin andvinyl polymers which have sufficient resiliency to accept and deflectthe blow of ice chips without material deterioration of the elastomericmaterial.

It is also apparent the greatest stress will be on mast 18. It must notonly bear the load of the bridge, but must bear the ice forces. Itshould, therefore, be of extra heavy reinforced construction. It will beappreciated, however, that since the path is narrow and the mast taperedto prevent wedging, the loads will be minimized relative to thatencountered by a conventional ice-cutting cargo vessel. This alsorepresents a minimization of the power requirements for ice breaking.

With reference to FIGS. 4 and 5, mast 18 may be provided with rudder orflap 92 which may be operated manually or by signal from a sensor suchas gyroscopic readily understood with reference to FIG. 7. In operation,semi-submerged transport system 10 travels in part through and under thesurface of ice 22. As illustrated, only the bridge and a portion of mast18 are surfaced. The submerged portions travel freely in the water andthey are not subject to wave actions, ice flows or the like. Asindicated, and on a relative basis, mast 18 is narrow and as aconsequence the amount of ice which must be cut to establish a paththrough ice 22 is small. In addition, since the mast is tapered in arearwardly direction there is little opportunity for jamming.

Virtually all that really is exposed is bridge 20 which presents, in awar-time situation, s small and inconspicuous target. In contrast,war-time vulnerability of tankers and pipelines would be extremely high.Further, the system is not vulnerable to ice flow compression damage asice is continuously being cut away. This eliminates pollution whichwould be caused by damage to a conventional type system.

The system also does not have to compensate for side drags imposed bywinds and currents which provide the further benefit in reduced powerand overall operating costs.

As major corrosion and scraping damage to icebreaking tankers wouldoccur at water-air interface, maintenance problems on a relative basisare substantially reduced. As only a portion of the system is at theinterface, it functions to cut a path through the ice to minimizeabrasion.

FIG. 8 represents one alternative embodiment of this invention. Insubstance, the propulsion section 16 which remains submerged andattached to mast l8 and bridge 20 are separated from cargo section 16 tofunction as an attending tug to tow the vessel through urnbilical cordtow line 96 which services the power re quirements of the navigationalaids contained in the towed navigational section 12. As the cargosection 14 must still be provided with some manipulative operations toadjust in depth and provide reduced thrust, most of the nagivationalaids provided in the unitized construction are retained by navigationalsection 12, namely, the diving vanes, thrust ports and sensorymechanisms which are used to sense and control depth through operationof diving vanes and thrust ports. The TV camera and lights formonitoring the forward motion of the system may be eliminated andprovided, as shown, in the attending propulsion section 16.

This system functions in the same manner as the unitized constructionbut some additional care must be taken during transport. For instance,should unusual ice conditions reach such that the ice-cutting systembecomes overloaded, the forward direction of the at tending tug may beslowed considerably. In this instance, umbilical cord 96 will becomeslack. The cargo vessel having a slight positive buoyancy will tend torise to come to rest at the underside of the ice. If excessive inertiaexists, thrust may be applied through port 34 in a downward directionand a reverse thrust through port 38 in conjunction with the operationof vanes 28 and 30 to direct the vessel towards the ice surface. As thecargo vessel is suitably protected with cushions it will, upon reachingthe surface, lose much of its inertia as a consequence of the frictionaleffect of being brought into contact with the ice.

Another embodiment is illustrated in FIG. 9 in which the tug and cargovessel are shown in separated relationship for a more detailedexplanation of the additional equipment which would be used for such anoperation.

Attending tug will have, as shown, a more blunt bow 98 to mate with acorresponding section at the stern on cargo section 14. Attending tug 36will also be provided with a series of coupling hooks 100 which serve tocouple and engage with cargo vessel 10. One of the hooks 102 isconnected to a retractable cable 104 to meet the situation where forwardmotion of the tug is resisted. The cargo vessel will be released andcable 104 will then be played out with the cargo vessel until it losesits inertia. Once the ice jam has been overcome, the tug may thenadvance to the cargo vessel by winding cable 104 and recoupling to it.During a released position, the tug must be capable of monitoring theposition of the cargo vessel. It is, therefore, provided with TV camera106 and lights 108 in order to observe the position of cargo vessel 10under the surface of the ice.

Since the cargo vessel is the forwardmost object in the travel of thetransport system it is also provided with TV camera 44 and lights 46which monitor its forward motion under the surface of the ice. These aswell as the electric motors required for the operation of vanes andthrust ports are energized by electrical conduit connections in thestern of cargo vessel which connect with mating connections 110 in thehow 98 of propulsion section 16.

These connections may, for instance, consist of a series of annularconductors separated by an elastomeric material. They are cone-shapedand compress upon mating with corresponding cone-shaped connectors onthe cargo vessel, the water-tight electrical connections being completeupon full compression.

FIG. 10 is an illustration of a servicing operation which can be usedfor loading and unloading of the semi-submerged cargo system in iceboundareas, With reference thereto, there is illustrated a servicing port 112having a master control cabin 114 and generally providing a landing pad116 for attending helicopters. The control cabin 114 is mounted onpedestal 118 which, in turn, is secured or anchored to the floor of theseaway. It is provided with pipeline communication to the shore for theloading and discharge of cargos. To protect service module 112 there isalso provided icecutting systems 120 which serve to cut any ice flowswhich may tend to damage or topple service module 112. As is shown,while one cargo vessel is being serviced, namely, either loaded orunloaded through service port 56, a towed cargo vessel is advanced tothe service port.

This demonstrates an advantage of the cargo transport system ofemploying a separate propulsion vessel, namely, that one tug may servicea number of vessels. As one is being emptied or filled, it may at onepoint, say, an icebound service port, be used to return carrying a fullvessel to a landside port or some point in an open water zone where thecargo vessel may be towed to a landside port by a surface vessel. It maythen, in exchange, receive an empty vessel or a vessel loaded with cargointended to be transported to the icebound area by transport under theice. Upon reaching the service module 112 where the returned vessel isunloaded and loaded, the tug picks up an already loaded cargo vessel forreturn to landside or ice-free port.

What is claimed is:

I. A transport system for the transportation of cargo under the surfaceof the ice which comprises:

1 1 a. a submergible cargo vessel comprising:

i. a navigational section containing means to adjust the depth of travelof said vessel; ii. a cargo section containing a plurality ofcompartments for the storage of cargo, means to load said cargocompartments and means to maintainthe vessel at a slight positivebuoyancy during transit;

b. means to propel said vessel, said means containing the prime sourceof power and comprising:

i. a submergible propulsion section;

ii. a surfaced bridge containing at least means to monitor and controlthe operation of the transport system and quarters for the operatingcrew;

iii. a mast rigidly connected to said propulsion section and saidsurfaced bridge, said mast containing forwardly positioned powered icecutting means movably mounted on said mast to chop ice into chips andform a path through ice which is at least coextensive with the width ofsaid mast, at least said ice cutting means being at an angle of fromabout to about 45 to the vertical in the bow direction to eliminate apitch force due to the ice chopping function of said powered ice cuttingmeans.

2. A transport system as claimed in claim 1 in which the means forpropelling said cargo vessel is an integral part of said cargo vessel.

3. A transportation system as claimed in claim 1 in which the means topropel said cargo vessel is detachable from said cargo vessel.

4. A transportation system as claimed in claim I in which. said cargovessel contains within the cargo section a plurality of upperlongitudinal flotation cargo tubes adapted for increasing buoyancy andlower longitudinal cargo-ballast tubes for decreasing buoyancy, tomaintain the cargo section at a positive buoyancy said upperlongitudinal flotation cargo tubes being above and said lowerlongitudinal cargo-ballast tubes being below said plurality ofcompartments for the storage of cargo.

5. A transportation system as claimed in claim 1 in which the cargocompartments are divided by flexible diaphragms.

6. A transportation system as claimed in claim 5 in which the cargocompartments comprise a plurality of longitudinally disposed tubes.

7. A transportation system as claimed in claim 1 in which the cargovessel is provided with at least one resilient, shock absorbing runnerextending longitudinally along at least a portion of the upper surfacethereof.

8. A semi-submerged transport system as claimed in claim 7 in which theshock absorbing runner comprises a foam core which decreases in densityin a vertical direction.

9. A transportation vessel as claimed in claim 1 in which the means toalter the depth of said cargo vessel include:

a. at least one set of diving vanes, and

b. at least one vertically disposed thrust port connecting the lower andupper surfaces of said navigation section, said thrust port containingmeans to induce a flow of water through said port.

10. A transportation system as claimed in claim 9 in combination with ahorizontally disposed thrust port extending from one side of saidnavigational section to the opposed side thereof, said horizontallydisposed thrust port intersecting said vertically disposed thrust portand'containing means to inducea flow of water therethrough and alongitudinally-thrust port extending from the bow of said navigationalsection and communicating with the intersection of said verticallydisposed thrust port and said horizontally disposed thrust port.

11. A transportation system as claimed in claim 1 in which theice-cutting means includes a pair of vertically disposed shafts, eachshaft containing a plurality of icechipping discs, the said shaftsadapted to rotate in an opposed direction, the forward peripheries ofeach disc rotating in an outboard direction.

12. A transportation system as claimed in claim 1 in which at least aportion of the prime source of power is contained in said normallysubmerged propulsion section.

13. A transportation system as claimed in claim 12 in which the primesources of power are gas turbines.

14. A transportation system as claimed in claim 1, in which the rigidlyconnecting mast is provided with an ice chip deflecting protective coverwhich is a reflective cover or an elastomeric coating.

15. A transportation system as claimed in claim 14 in which thereflective cover comprises a glass fiber reinforced resin.

16. A submergible cargo vessel for the transporting of cargo under thesurface of the ice which comprises:

a. a navigational section positioned in the bow of said cargo vessel andto adjust the depth of travel of said vessel;

b. a cargo section containing a plurality of compartments for thestorage of cargo, means to load said cargo compartments and means tomaintain the vessel at a slight positive buoyancy during transit, saidcargo vessel having longitudinally disposed along the upper surfacethereof at least one longitudinally extending resilient runner having:

i. an open cell flexible foam core which decreases in density in avertical direction;

ii. a flexible permeable web securing said core to the upper surface ofsaid cargo vessel;

iii. an abrasion resistant flexible coating on the upper surface of saidretaining web.

17. A submergible cargo vessel as claimed in claim 16 in which saidcargo section contains a plurality of upper longitudinal flotation cargotubes adapted for increasing buoyancy and lower longitudinalcargo-ballast tubes for decreasing buoyancy.

18. A submergible cargo vessel as claimed in claim 16 in which the cargocompartments are divided by flexible diaphragms.

19. A submergible cargo vessel as claimed in claim 16 in which the cargocompartments are longitudinal tubes.

20. A submergible cargo vessel as claimed in claim 16 in which the meansto alter the depth of said cargo vessel include:

a. at least one set of diving vanes and b. at least one verticallydisposed thrust port connecting the lower and upper surfaces of saidnavigation section, said thrust port containing meansto induce a flow ofwater through said port.

21. A submergible cargo system as claimed in claim 20 in combinationwith a horizontally disposed thrust port extending from one side of saidnavigational section to the opposed side thereof, said horizontallydisposed thrust port intersecting said vertically disposed thrust portand containing means to induce a flow of water therethrough and alongitudinally thrust port extending from the bow of said navigationsection and communicating with the intersection of said verticallydisposed thrust port and said horizontally disposed thrust port.

22. A semi-submerged transport system for the transportation of cargounder the surface of ice which comprises:

a. a submergible cargo vessel comprising:

i. a navigational section containing means to adjust the depth of travelof said cargo vessel, said means including at least one set of divingvanes and at least one vertically disposed thrust port connecting thelower and upper surfaces of said navigational section, said thrust portcontaining means to induce a flow of water through said thrust port;

ii. a cargo section containing a plurality of compartments for thestorage of cargo, means to load said cargo compartments and means tomaintain the cargo vessel at a slight positive buoyancy during transit;

b, means to propel said cargo vessel, said means containing the primesource of power and comprising:

i. a submergible propulsion section;

ii. a surfaced bridge containing at least means to monitor and controlthe operation of the transport system and quarters for the operatingcrew;

iii. a mast rigidly connected to said propulsion section and saidsurfaced bridge, said mast containing fowardly positioned powered icecutting means movably mounted on said mast to chop ice into chips andform a path through ice which is at least coextensive with the width ofsaid mast, at least said ice cutting means being at an angle of fromabout to about 45 to the vertical in the bow direction to eliminate apitch force due to the ice chopping function of said powered ice cuttingmeans.

23. A semi-submerged transport system as claimed in claim 22 in whichthe means to adjust the depth of travel contained in the navigationalsection includes a horizontally disposed thrust port extending from oneside of said navigational section to the opposed side thereof, saidhorizontally disposed thrust port intersecting said vertically disposedthrust port and containing means to induce a flow of water therethroughand a longitudinally thrust port extending from the bow of saidnavigation section and communicating with the intersection of saidvertically disposed thrust port and said horizontally disposed thrustport.

24. A semi-submerged transport system as claimed in claim 22 in whichthe mast is protected against projected ice chips by a reflective coveror an elastomeric coating.

25. A semi-submerged transport system as claimed in claim 24 in whichthe reflective cover comprises a glass fiber reinforced resin.

26. A semi-submerged tug for propelling a submerged vessel under icewhich comprises:

a. a submergible propulsion section including means to couple with saidsubmerged vessel;

b. a surfaced bridge containing at least means to monitor the positionof said submerged vessel,

means to control the operation of said tug and quarters for theoperating crew;

c. a mast rigidly connected to said propulsion section and said surfacedbridge, said mast containing forwardly positioned powered ice cuttingmeans movably mounted on said mast to chop ice into chips and form apath through ice which is at least coextensive with the width of saidmast, at least said ice cutting means being at an angle of from about 10to about 45 to the vertical in the bow direction to eliminate a pitchforce due to the ice chopping function of said powered ice cutting meansand said tug containing a prime means of power to propel a submerbedvessel under ice.

27. A semi-submerged tug as claimed in claim 26 in which at least partof the prime means of power is contained in the propulsion section.

28. A semi-submerged tug as claimed in claim 27 in which the primesources of power are gas turbines.

29. A semi-submerged tug as claimed in claim 26 in which the ice-cuttingmeans includes a pair of vertically disposed shafts each shaftcontaining a plurality of icechipping discs, the said shafts adapted torotate in an opposed direction, the forward peripheries of each discrotating in an outboard direction.

30. A semi-submerged tug as claimed in claim 26 in which the mast isprotected against chips of ice by a re flective protective cover orelastomeric coating.

31. A semi-submerged tug as claimed in claim 30 in which the reflectiveprotective cover comprises a glass fiber reinforced resin.

32. A transport system for the transportation of cargo under the surfaceof the ice which comprises:

A. a submergible cargo vessel comprising:

i. a navigational section containing means to adjust the depth of travelof said vessel;

ii. a cargo section containing a plurality of compartments for thestorage of cargo, means to load said cargo compartments and means tomaintain the vessel at a slight positive buoyancy during transit, saidcargo vessel having longitudinally disposed along the upper surfacethereof at least one longitudinally extending resilient runner having:

a. an open cell flexible foam core which decreases in density in avertical direction;

b. a flexible permeable web securing said core to the upper surface ofsaid cargo vessel;

c. an abrasion resistant flexible coating on the upper surface of saidretaining web,

B. means to propel said vessel, said means containing the prime sourceof power and comprising:

i. a submergible propulsion section;

ii. a surfaced bridge containing at least means to monitor and controlthe operation of the transport system and quarters for the operatingcrew;

iii. a mast rigidly connected to said propulsion sec tion and saidsurfaced bridge, said mast containing forwardly positioned powered icecutting means movably mounted on said mast to chop ice into chips andform a path through ice which is at least coextensive with the width ofsaid mast.

33. A transport system as claimed in claim 32 in which the means forpropelling said cargo vessel is an integral part of said cargo vessel.-

15 34. A transportation system as claimed in claim 32 in which the meansto propel said cargo vessel is detachable from said cargo vessel.

35. A transport system for the transportation of cargo under the surfaceof the ice which comprises:

a. a submergible cargo vessel comprising:

i. a navigational section containing means to adjust the depth of travelof said vessel;

ii. a cargo section containing a plurality of compartments for thestorage of cargo, means to load said cargo compartments and means tomaintain the vessel at a slight positive buoyancy during transit;

b. means to propel said vessel, said means containing the prime sourceof power and comprising;

i. a submergible porpulsion section;

ii. a surfaced bridge containing at least means to monitor and controlthe operation of the transport system and quarters for the operatingcrew;

iii. a mast rigidly connected to said propulsion section and saidsurfaced bridge, said mast containing forwardly positioned powered icecutting means including a pair of inclined vertically disposed shafts,each shaft containing a plurality of ice chipping discs, the said shaftsadapted to rotate in an opposed direction, the forward peripheries ofeach disc rotating in an outboard direction to chop ice into chips andexpel said ice chips to form a path through ice which is at leastcoextensive with the width of said mast.

36. A transport system as claimed in claim 35 in which the inclinedvertically disposed shafts are disposed at an angle of from about toabout 45 degrees to the vertical in the bow direction to eliminate apitch force due to the ice chopping function of said powered ice cuttingmeans.

37. A semi-submerged transport system as claimed in claim 35 in whichthe mast is protected against chips of ice by a reflective protectivecover or an elastomeric coating.

38. A semi-submerged transport system as claimed in claim 37 in whichthe reflective protective cover comprises a glass fiber reinforcedresin.

39. A semi-submerged transport system for the transportation of cargounder the surface of ice which comprises:

a. a submergible cargo vessel comprising:

i. a navigational section containing means to adjust the depth of travelof said cargo vessel, said means including at least one set of divingvanes and at least one vertically disposed thrust port connecting thelower and upper surfaces of said navigational section, said thrust portcontaining means to induce a flow of water through said thrust port; acargo section containing a plurality of compartments for the storage ofcargo, means to load said cargo compartments and meant to maintain thecargo vessel at a slight positive buoyancy during transit;

b. means to propel said cargo vessel, said means containing the primesource of power and comprising: i. a submergible propulsion section; ii.a surfaced bridge containing at least means to monitor and control theoperation of the transport system and quarters for the operating crew;

iii. a mast rigididly connectedto said propulsion section and saidsurfaced bridge, said mast containing forwardly positioned powered icecutting means including a pair of inclined vertically disposed shafts,each shaft containing a plurality of ice chipping discs, the said shaftsadapted to rotate in a opposed direction, the forward peripheries ofeach disc rotating in an outboard direction to chop ice into chips andexpel said ice chips to form a path through ice which is at leastcoextensive with the width of said mast.

40. A semi-submerged transport system as claimed in claim 39 in whichthe forwardly positioned means to cut a path through ice is disposed atan angle from about 10 to about 45 to the vertical in the bow directionto eliminate a pitch force due to the ice chopping function of saidpowered ice cutting means.

41. A semi-submerged transport system as claimed in claim 39 in whichthe mast is protected against projected ice chips by a reflective coveror an elastomeric coating.

42. A semi-submerged tug for propelling a submerged vessel under icewhich comprises:

a. a submergible propulsion section including means to couple with saidsubmerged vessel;

b. a surfaced bridge containing at least means to monitor the positionof said submerged vessel, means to control the operation of said tug andquarters for the operating crew;

c. a mast rigidly connected to said propulsion section and said surfacedbridge, said mast containing forwardly positioned powered ice cuttingmeans including a pair of inclined vertically disposed shafts, eachshaft containing a plurality of ice chipping discs, the said shaftsadapted to rotate in an op posed direction, the forward peripheries ofeach disc rotating in an outboard direction to chop ice into chips andexpel said ice chips to form a path through ice which is at leastcoextensive with the width of said mast.

43. A semi-submerged tug as claimed in claim 42 in which the mast isprotected against chips of ice by a reflective protective cover orelastomeric coating.

44. A semi-submerged tug as claimed in claim 42 in which the forwardlypositioned means to cut a path through ice is disposed at an angle offrom about 10 to about 45 to the horizontal in the bow direction toeliminate a pitch force due to the ice chopping function of said poweredice cutting means.

45. A semi-submerged tug as claimed in claim 44 in which the mast isprotected against chips of ice by a reflective protective cover orelastomeric coating.

46. A semi-submerged tug as claimed in claim 45 in which the reflectiveprotective cover comprises a glass fiber reinforced resin.

"H050 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION atent NO-3,868,920 Dated March 4, 1975 Inventor) Joseph F. Schirtzinger It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 4, line 64, "porvided" should read -provided.

Column 9, line 13, "5" should read a-.

Column 15, line 58, "meant" should read means-.

Column 16, line 12, "a" should read an--.

Signed and sealed this 10th day of June 1975.

(SEAL) Attest:

C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officerand Trademarks

1. A transport system for the transportation of cargo under the surfaceof the ice which comprises: a. a submergible cargo vessel comprising: i.a navigational section containing means to adjust the depth of travel ofsaid vessel; ii. a cargo section containing a plurality of compartmentsfor the storage of cargo, means to load said cargo compartments andmeans to maintain the vessel at a slight positive buoyancy duringtransit; b. means to propel said vessel, said means containing the primesource of power and comprising: i. a submergible propulsion section; ii.a surfaced bridge containing at least means to monitor and control theoperation of the transport system and quarters for the operating crew;iii. a mast rigidly connected to said propulsion section and saidsurfaced bridge, said mast containing forwardly positioned powered icecutting means movably mounted on said mast to chop ice into chips andform a path through ice which is at least coextensive with the width ofsaid mast, at least said ice cutting means being at an angle of fromabout 10* to about 45* to the vertical in the bow direction to eliminatea pitch force due to the ice chopping function of said powered icecutting means.
 2. A transport system as claimed in claim 1 in which themeans for propelling said cargo vessel is an integral part of said cargovessel.
 3. A transportation system as claimed in claim 1 in which themeans to propel said cargo vessel is detachable from said cargo vessel.4. A transportation system as claimed in claim 1 in which said cargovessel contains within the cargo section a plurality of upperlongitudinal flotation cargo tubes adapted for increasing buoyancy andlower longitudinal cargo-ballast tubes for decreasing buoyancy, tomaintain the cargo section at a positive buoyancy said upperlongitudinal flotation cargo tubes being above and said lowerlongitudinal cargo-ballast tubes being below said plurality ofcompartments for the storage of cargo.
 5. A transportation system asclaimed in claim 1 in which the cargo compartments are divided byflexible diaphragms.
 6. A transportation system as claimed in claim 5 inwhich the cargo compartments comprise a plurality of longitudinallydisposed tubes.
 7. A transportation system as claimed in claim 1 inwhich the cargo vessel is provided with at least one resilient, shockabsorbing runner extending longitudinally along at least a portion ofthe upper surface thereof.
 8. A semi-submerged transport system asclaimed in claim 7 in which the shock absorbing runner comprises a foamcore which decreases in density in a vertical direction.
 9. Atransportation vessel as claimed in claim 1 in which the means to alterthe depth of said cargo vessel include: a. at least one set of divingvanes, and b. at least one vertically disposed thrust port connectingthe lower and upper surfaces of said navigation section, said thrustport containing means to induce a flow of water through said port.
 10. Atransportation system as claimed in claim 9 in combination with ahorizontally disposed thrust port extending from one side of saidnavigational section to the opposed side thereof, said horizontallydisposed thrust port intersecting said vertically disposed thrust portand containing means to induce a flow of water therethrough and alongitudinally thrust port extending from the bow of said navigationalsection and communicating with the intersection of said verticallydisposed thrust port and said horizontally disposed thrust port.
 11. Atransportation system as claimed in claim 1 in which the ice-cuttingmeans includes a pair of vertically disposed shafts, each shaftcontaining a plurality of ice-chipping discs, the said shafts adapted torotate in an opposed direction, the forward peripheries of each discrotating in an outboard direction.
 12. A transportation system asclaimed in claim 1 in which at least a portion of the prime source ofpower is contained in said normally submerged propulsion section.
 13. Atransportation system as claimed in claim 12 in which the prime sourcesof power are gas turbines.
 14. A transportation system as claimed inclaim 1, in which the rigidly connecting mast is provided with an icechip deflecting protective cover which is a reflective cover or anelastomeric coating.
 15. A transportation system as claimed in claim 14in which the reflective cover comprises a glass fiber reinforced resin.16. A submergible cargo vessel for the transporTing of cargo under thesurface of the ice which comprises: a. a navigational section positionedin the bow of said cargo vessel and to adjust the depth of travel ofsaid vessel; b. a cargo section containing a plurality of compartmentsfor the storage of cargo, means to load said cargo compartments andmeans to maintain the vessel at a slight positive buoyancy duringtransit, said cargo vessel having longitudinally disposed along theupper surface thereof at least one longitudinally extending resilientrunner having: i. an open cell flexible foam core which decreases indensity in a vertical direction; ii. a flexible permeable web securingsaid core to the upper surface of said cargo vessel; iii. an abrasionresistant flexible coating on the upper surface of said retaining web.17. A submergible cargo vessel as claimed in claim 16 in which saidcargo section contains a plurality of upper longitudinal flotation cargotubes adapted for increasing buoyancy and lower longitudinalcargo-ballast tubes for decreasing buoyancy.
 18. A submergible cargovessel as claimed in claim 16 in which the cargo compartments aredivided by flexible diaphragms.
 19. A submergible cargo vessel asclaimed in claim 16 in which the cargo compartments are longitudinaltubes.
 20. A submergible cargo vessel as claimed in claim 16 in whichthe means to alter the depth of said cargo vessel include: a. at leastone set of diving vanes and b. at least one vertically disposed thrustport connecting the lower and upper surfaces of said navigation section,said thrust port containing means to induce a flow of water through saidport.
 21. A submergible cargo system as claimed in claim 20 incombination with a horizontally disposed thrust port extending from oneside of said navigational section to the opposed side thereof, saidhorizontally disposed thrust port intersecting said vertically disposedthrust port and containing means to induce a flow of water therethroughand a longitudinally thrust port extending from the bow of saidnavigation section and communicating with the intersection of saidvertically disposed thrust port and said horizontally disposed thrustport.
 22. A semi-submerged transport system for the transportation ofcargo under the surface of ice which comprises: a. a submergible cargovessel comprising: i. a navigational section containing means to adjustthe depth of travel of said cargo vessel, said means including at leastone set of diving vanes and at least one vertically disposed thrust portconnecting the lower and upper surfaces of said navigational section,said thrust port containing means to induce a flow of water through saidthrust port; ii. a cargo section containing a plurality of compartmentsfor the storage of cargo, means to load said cargo compartments andmeans to maintain the cargo vessel at a slight positive buoyancy duringtransit; b. means to propel said cargo vessel, said means containing theprime source of power and comprising: i. a submergible propulsionsection; ii. a surfaced bridge containing at least means to monitor andcontrol the operation of the transport system and quarters for theoperating crew; iii. a mast rigidly connected to said propulsion sectionand said surfaced bridge, said mast containing fowardly positionedpowered ice cutting means movably mounted on said mast to chop ice intochips and form a path through ice which is at least coextensive with thewidth of said mast, at least said ice cutting means being at an angle offrom about 10* to about 45* to the vertical in the bow direction toeliminate a pitch force due to the ice chopping function of said poweredice cutting means.
 23. A semi-submerged transport system as claimed inclaim 22 in which the means to adjust the depth of travel contained inthe navigational section includes a horizontally disposed thrust portextending from one side of said navigational section to the opposed sidethereof, said horizontally disposed thrust port intersecting saidvertically disposed thrust port and containing means to induce a flow ofwater therethrough and a longitudinally thrust port extending from thebow of said navigation section and communicating with the intersectionof said vertically disposed thrust port and said horizontally disposedthrust port.
 24. A semi-submerged transport system as claimed in claim22 in which the mast is protected against projected ice chips by areflective cover or an elastomeric coating.
 25. A semi-submergedtransport system as claimed in claim 24 in which the reflective covercomprises a glass fiber reinforced resin.
 26. A semi-submerged tug forpropelling a submerged vessel under ice which comprises: a. asubmergible propulsion section including means to couple with saidsubmerged vessel; b. a surfaced bridge containing at least means tomonitor the position of said submerged vessel, means to control theoperation of said tug and quarters for the operating crew; c. a mastrigidly connected to said propulsion section and said surfaced bridge,said mast containing forwardly positioned powered ice cutting meansmovably mounted on said mast to chop ice into chips and form a paththrough ice which is at least coextensive with the width of said mast,at least said ice cutting means being at an angle of from about 10* toabout 45* to the vertical in the bow direction to eliminate a pitchforce due to the ice chopping function of said powered ice cutting meansand said tug containing a prime means of power to propel a submerbedvessel under ice.
 27. A semi-submerged tug as claimed in claim 26 inwhich at least part of the prime means of power is contained in thepropulsion section.
 28. A semi-submerged tug as claimed in claim 27 inwhich the prime sources of power are gas turbines.
 29. A semi-submergedtug as claimed in claim 26 in which the ice-cutting means includes apair of vertically disposed shafts each shaft containing a plurality ofice-chipping discs, the said shafts adapted to rotate in an opposeddirection, the forward peripheries of each disc rotating in an outboarddirection.
 30. A semi-submerged tug as claimed in claim 26 in which themast is protected against chips of ice by a reflective protective coveror elastomeric coating.
 31. A semi-submerged tug as claimed in claim 30in which the reflective protective cover comprises a glass fiberreinforced resin.
 32. A transport system for the transportation of cargounder the surface of the ice which comprises: A. a submergible cargovessel comprising: i. a navigational section containing means to adjustthe depth of travel of said vessel; ii. a cargo section containing aplurality of compartments for the storage of cargo, means to load saidcargo compartments and means to maintain the vessel at a slight positivebuoyancy during transit, said cargo vessel having longitudinallydisposed along the upper surface thereof at least one longitudinallyextending resilient runner having: a. an open cell flexible foam corewhich decreases in density in a vertical direction; b. a flexiblepermeable web securing said core to the upper surface of said cargovessel; c. an abrasion resistant flexible coating on the upper surfaceof said retaining web, B. means to propel said vessel, said meanscontaining the prime source of power and comprising: i. a submergiblepropulsion section; ii. a surfaced bridge containing at least means tomonitor and control the operation of the transport system and quartersfor the operating crew; iii. a mast rigidly connected to said propulsionsection and said surfaced bridge, said mast containing forwardlypositioned powered ice cutting means movably mounted on said mast tochop ice into chips and form a path through ice which is at leastcoextensive with the width of said mast.
 33. A transport system asclaimed in claiM 32 in which the means for propelling said cargo vesselis an integral part of said cargo vessel.
 34. A transportation system asclaimed in claim 32 in which the means to propel said cargo vessel isdetachable from said cargo vessel.
 35. A transport system for thetransportation of cargo under the surface of the ice which comprises: a.a submergible cargo vessel comprising: i. a navigational sectioncontaining means to adjust the depth of travel of said vessel; ii. acargo section containing a plurality of compartments for the storage ofcargo, means to load said cargo compartments and means to maintain thevessel at a slight positive buoyancy during transit; b. means to propelsaid vessel, said means containing the prime source of power andcomprising; i. a submergible porpulsion section; ii. a surfaced bridgecontaining at least means to monitor and control the operation of thetransport system and quarters for the operating crew; iii. a mastrigidly connected to said propulsion section and said surfaced bridge,said mast containing forwardly positioned powered ice cutting meansincluding a pair of inclined vertically disposed shafts, each shaftcontaining a plurality of ice chipping discs, the said shafts adapted torotate in an opposed direction, the forward peripheries of each discrotating in an outboard direction to chop ice into chips and expel saidice chips to form a path through ice which is at least coextensive withthe width of said mast.
 36. A transport system as claimed in claim 35 inwhich the inclined vertically disposed shafts are disposed at an angleof from about 10 to about 45 degrees to the vertical in the bowdirection to eliminate a pitch force due to the ice chopping function ofsaid powered ice cutting means.
 37. A semi-submerged transport system asclaimed in claim 35 in which the mast is protected against chips of iceby a reflective protective cover or an elastomeric coating.
 38. Asemi-submerged transport system as claimed in claim 37 in which thereflective protective cover comprises a glass fiber reinforced resin.39. A semi-submerged transport system for the transportation of cargounder the surface of ice which comprises: a. a submergible cargo vesselcomprising: i. a navigational section containing means to adjust thedepth of travel of said cargo vessel, said means including at least oneset of diving vanes and at least one vertically disposed thrust portconnecting the lower and upper surfaces of said navigational section,said thrust port containing means to induce a flow of water through saidthrust port; ii. a cargo section containing a plurality of compartmentsfor the storage of cargo, means to load said cargo compartments andmeant to maintain the cargo vessel at a slight positive buoyancy duringtransit; b. means to propel said cargo vessel, said means containing theprime source of power and comprising: i. a submergible propulsionsection; ii. a surfaced bridge containing at least means to monitor andcontrol the operation of the transport system and quarters for theoperating crew; iii. a mast rigididly connected to said propulsionsection and said surfaced bridge, said mast containing forwardlypositioned powered ice cutting means including a pair of inclinedvertically disposed shafts, each shaft containing a plurality of icechipping discs, the said shafts adapted to rotate in a opposeddirection, the forward peripheries of each disc rotating in an outboarddirection to chop ice into chips and expel said ice chips to form a paththrough ice which is at least coextensive with the width of said mast.40. A semi-submerged transport system as claimed in claim 39 in whichthe forwardly positioned means to cut a path through ice is disposed atan angle from about 10* to about 45* to the vertical in the bowdirection to eliminate a pitch force due to the ice chopping function ofsaid powered ice cutting meaNs.
 41. A semi-submerged transport system asclaimed in claim 39 in which the mast is protected against projected icechips by a reflective cover or an elastomeric coating.
 42. Asemi-submerged tug for propelling a submerged vessel under ice whichcomprises: a. a submergible propulsion section including means to couplewith said submerged vessel; b. a surfaced bridge containing at leastmeans to monitor the position of said submerged vessel, means to controlthe operation of said tug and quarters for the operating crew; c. a mastrigidly connected to said propulsion section and said surfaced bridge,said mast containing forwardly positioned powered ice cutting meansincluding a pair of inclined vertically disposed shafts, each shaftcontaining a plurality of ice chipping discs, the said shafts adapted torotate in an opposed direction, the forward peripheries of each discrotating in an outboard direction to chop ice into chips and expel saidice chips to form a path through ice which is at least coextensive withthe width of said mast.
 43. A semi-submerged tug as claimed in claim 42in which the mast is protected against chips of ice by a reflectiveprotective cover or elastomeric coating.
 44. A semi-submerged tug asclaimed in claim 42 in which the forwardly positioned means to cut apath through ice is disposed at an angle of from about 10* to about 45*to the horizontal in the bow direction to eliminate a pitch force due tothe ice chopping function of said powered ice cutting means.
 45. Asemi-submerged tug as claimed in claim 44 in which the mast is protectedagainst chips of ice by a reflective protective cover or elastomericcoating.
 46. A semi-submerged tug as claimed in claim 45 in which thereflective protective cover comprises a glass fiber reinforced resin.